One possibility is that it is a short story based on the "Car Wars" board game by Steve Jackson.
They also published a Magazine of game ideas and short stories 4x a year called "American AutoDuel Quarterly" (AADQ) that lasted for 10 years. (1983-1992)
Society is collapsing (not as bad as Road Warrior) but just about every one has weapons built into to their cars/trucks/motorcycles, etc to protect themselves on the road.
The story sounds Very much like the sort of stories they would have included in the magazine.
The premise of the game and magazine is its set in 2030s